The invention relates to an amplifier-mixer device comprising: an amplifier structure having at least one amplifier input and at least one amplifier output, while at least one amplifier output is looped back via a feedback to at least one amplifier input, which amplifier structure comprises a mixer structure, having at least one radio input communicatively connected with the amplifier input, for receiving a signal of a radio frequency; at least one local input for receiving a local oscillator signal; and at least one mixer output for providing a signal of a medium frequency.
Such an amplifier-mixer device is known from the Dutch-language publication: “A bipolar switching mixer with overall feedback”, W. Muys, graduate report 68360/1990-10, Delft University of Technology 1989.
In the known amplifier-mixer device, the amplifier structure is designed as a two-stage amplifier in which a Common Base (CB) bipolar junction transistor (BJT), of which the collector and emitter form the amplifier output, is replaced by a mixer structure. The mixer structure is designed as a Gilbert Cell mixer and comprises two BJTs whose emitters are connected to each other. Of each of the BJTs, the base is connected to a separate local oscillator source. These local oscillator sources are connected to each other through a side not connected to any of the bases, and operate in opposite phase. The mutually connected sides of the local oscillator sources in the amplifier, as it were, replace the base of the CB bipolar transistor. The collectors of the BJTs constitute the positive and the negative junction, respectively, of the medium frequency output.
A drawback of this known amplifier-mixer device is the energy consumption. This is disadvantageous specifically in applications with a limited source power, such as mobile telephones, radios or other wireless applications. Moreover, the known amplifier-mixer device is comparatively complex.